Hydrogen production and purification for dimethyl ether autothermal reformer using membrane reactor

In this research, the thermodynamic analysis of the dimethyl ether (DME) autothermal reforming (ATR) in a membrane-packed catalyst bed was carried out for hydrogen production and purification. The purification was performed using semipermeable membrane made of Pd/Ag with a thickness of 50 μm and a length of 30 cm. A CFD model was developed to simulate the distribution of hydrogen concentration gradients spatially, and the chemical reaction mechanism of autothermal reforming of dimethyl ether to produce hydrogen was explored. The effects of several critical operating parameters (temperature, mass flow rate, and sweep gas ratio) were investigated in terms of DME conversion and hydrogen recovery. The purification process of hydrogen permeating through a semi-permeable membrane was optimized by changing the inlet mass flow rate of the permeate side purge steam. The simulation results show that the dimethyl ether is nearly completely converted at a temperature of 400℃, meanwhile increasing the inlet flow rate of the sweep steam (e.g., 10 times that of the reaction side) can effectively improve the hydrogen purification efficiency thereby reducing the residual hydrogen content in the syngas.